HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: 585/1/103    most recent jphysiol.2007.141788v1 Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Frick, A. Articles by Sakmann, B. Search for Related Content PubMed PubMed Citation Articles by Frick, A. Articles by Sakmann, B. Related Collections Neuroscience

¹ Abteilung Zellphysiologie, Max-Planck-Institut für Medizinische Forschung, D-69120 Heidelberg, Germany
² Research Centre Juelich, Institute of Neuroscience and Biophysics INB-3, Department of Medicine, D-52425 Juelich, Germany

The probability of synaptic transmitter release determines the spread of excitation and the possible range of computations at unitary connections. To investigate whether synaptic properties between neocortical pyramidal neurons change during the assembly period of cortical circuits, whole-cell voltage recordings were made simultaneously from two layer 5A (L5A) pyramidal neurons within the cortical columns of rat barrel cortex. We found that synaptic transmission between L5A pyramidal neurons is very reliable between 2 and 3 weeks of postnatal development with a mean unitary EPSP amplitude of 1.2 mV, but becomes less efficient and fails more frequently in the more mature cortex of 4 weeks of age with a mean unitary EPSP amplitude of 0.65 mV. Coefficient of variation and failure rate increase as the unitary EPSP amplitude decreases during development. The paired-pulse ratio (PPR) of synaptic efficacy at 10 Hz changes from 0.7 to 1.04. Despite the overall increase in PPR, short-term plasticity displays a large variability at 4 weeks, ranging from strong depression to strong facilitation (PPR, range 0.6–2.1), suggesting the potential for use-dependent modifications at this intracortical synapse. In conclusion, the transmitter release probability at the L5A–L5A connection is developmentally regulated in such a way that in juvenile animals excitation by single action potentials is efficiently transmitted, whereas in the more mature cortex synapses might be endowed with a diversity of filtering characteristics.

(Received 29 July 2007; accepted after revision 27 September 2007; first published online 4 October 2007)
Corresponding author A. Frick: Max-Planck-Institut für Medizinische Forschung, Abteilung Zellphysiologie, Jahnstrasse 29, 69120 Heidelberg, Germany.  Email: andreas.frick{at}mpimf-heidelberg.mpg.de

This article has been cited by other articles:

				A.-M. M. Oswald and A. D. Reyes Maturation of Intrinsic and Synaptic Properties of Layer 2/3 Pyramidal Neurons in Mouse Auditory Cortex J Neurophysiol, June 1, 2008; 99(6): 2998 - 3008. [Abstract] [Full Text] [PDF]

				H. Sato, Y. Shimanuki, M. Saito, H. Toyoda, T. Nokubi, Y. Maeda, T. Yamamoto, and Y. Kang Differential Columnar Processing in Local Circuits of Barrel and Insular Cortices J. Neurosci., March 19, 2008; 28(12): 3076 - 3089. [Abstract] [Full Text] [PDF]